A group service provides a user with communication information in batch. When a group is set, the user may transmit messages (including short messages, multimedia messages, instant message or emails), or initiate multiparty conferences or Push-to-talk over Cellular (PoC) calls using the group service. In the group service, a group member or a user outside the group may share basic information of the group to a certain extent according to a group policy. The basic information of the group (i.e. the basic group information) includes a group attribute, a group member list and a group member attribute.
A presence service is a communication service for collecting and publishing presence information. The presence information includes user willingness information, network connection status information, etc. The user willingness information includes a status attribute indicating communication willingness of a user, such as willing or not willing. The user willingness information also includes willingness information relevant to specified applications, such as willing for PoC or not willing for Instant Messaging (IM). The user willingness information is managed by a user. The network connection status information includes a status attribute of the connection between user equipment and the network, e.g., whether the user equipment is powered on, whether the user is in the service area, whether the user has logged on to an IM system. The network connection status information is controlled by the network. The presence information may further include: one or multiple contact manners and addresses (e.g., telephone numbers or email addresses), location information, personal information of the user (e.g., moods, favorites, languages, icons, etc.), time zone of the user and terminal capacity of the user. An entity subscribing to the presence information is called watcher and an entity publishing the presence information is called presentity.
In the prior art, the group service and the presence service are independent of each other. A user can only share the basic information of his home group through the group service, and the user can only acquire the presence information of the user himself through the presence service. When a group member wishes to acquire the presence information of a second member in the group, the group member has to submit a request to a presence server, and the presence server verifies the identity and right of the group member to determine whether to provide the presence information of the second group member for the group member. When the group member wishes to acquire the presence information of all the other members in the group, the group member has to submit a request to the presence server again and again for the presence information of each of all the other members. The presence server should verify the identity and right of the group member each time the group member summits a request. The whole process will be lengthy and inconvenient for sharing presence information in the group.